1. Field of the Invention
The present invention relates to the field of packaging powdered products, notably into bags.
2. Description of the Prior Art
Powdered products or those having a high tendency to become mixed with air during operations of transportation and weighing pose problems in bagging, notably into bags of plastics material or of paper.
The proportion of air that they carry causes a considerable increase in their volume, which necessitates, in the majority of cases, the use of bags of greater capacity than would be required by the same product restored to its true density.
An attempt has already been made to resolve this problem by forming on bags of the "open mouth" type a hole in one of its surfaces at the level of the place where the closing of the bag would be effected by welding and/or sewing and by forming, on the bagging mouth of the filling or packaging machine, an air passage corresponding to that of the bag when the latter is held by the bag-holder, a vacuum pump sucking air mixed with the product during the whole time of filling, after which the said hole was hermetically closed simultaneously with the mouth of the bag.
However, such a device does not give complete satisfaction on account of the difficulty of maintaining the area of the bag intended to be sealed by welding free of particles of product due to the fact of the implantation of the vacuum applying system inside the bag during its filling. The lips of the bag intended to be welded remain in fact more-or-less polluted which spoils the quality of the welding.
It is an object of the invention to overcome this drawback by providing a machine for the bagging of powdered products in bags of the "open mouth" type of plastics material, the inside of the bag in the course of filling being subjected to pumping of the air entrained by the product, the bag welding areas being preserved from any contact with the product in the course of the bag-filling operation.
It is also an object of the invention to provide a machine ensuring complete automatization of the bagging process from the taking of the bag until its welding, the various operations being carried out at high speed and with great reliability.